资源环境科技发展态势分析平台

Graphene films grown by chemical vapour deposition have unusual physical and chemical properties that offer promise for applications such as flexible electronics and high-frequency transistors(1-10). However, wrinkles invariably form during growth because of the strong coupling to the substrate, and these limit the large-scale homogeneity of the film(1-4,11,12). Here we develop a proton-assisted method of chemical vapour deposition to grow ultra-flat graphene films that are wrinkle-free. Our method of proton penetration(13-17) and recombination to form hydrogen can also reduce the wrinkles formed during traditional chemical vapour deposition of graphene. Some of the wrinkles disappear entirely, owing to the decoupling of van der Waals interactions and possibly an increase in distance from the growth surface. The electronic band structure of the as-grown graphene films shows a V-shaped Dirac cone and a linear dispersion relation within the atomic plane or across an atomic step, confirming the decoupling from the substrate. The ultra-flat nature of the graphene films ensures that their surfaces are easy to clean after a wet transfer process. A robust quantum Hall effect appears even at room temperature in a device with a linewidth of 100 micrometres. Graphene films grown by proton-assisted chemical vapour deposition should largely retain their intrinsic performance, and our method should be easily generalizable to other nanomaterials for strain and doping engineering.

The authors identify an increased hepatic NADH/NAD(+) ratio as an underlying metabolic parameter that is shaped by human genetic variation and contributes causally to key metabolic traits and diseases.

Whole-genome sequencing of normal human endometrial glands shows that most are clonal cell populations and frequently carry cancer driver mutations that occur early in life, and that parity has a protective effect.

Adipose tissue is an energy store and a dynamic endocrine organ(1,2). In particular, visceral adipose tissue (VAT) is critical for the regulation of systemic metabolism(3,4). Impaired VAT function-for example, in obesity-is associated with insulin resistance and type 2 diabetes(5,6). Regulatory T (T-reg) cells that express the transcription factor FOXP3 are critical for limiting immune responses and suppressing tissue inflammation, including in the VAT(7-9). Here we uncover pronounced sexual dimorphism in T-reg cells in the VAT. Male VAT was enriched for T-reg cells compared with female VAT, and T-reg cells from male VAT were markedly different from their female counterparts in phenotype, transcriptional landscape and chromatin accessibility. Heightened inflammation in the male VAT facilitated the recruitment of T-reg cells via the CCL2-CCR2 axis. Androgen regulated the differentiation of a unique IL-33-producing stromal cell population specific to the male VAT, which paralleled the local expansion of T-reg cells. Sex hormones also regulated VAT inflammation, which shaped the transcriptional landscape of VAT-resident T-reg cells in a BLIMP1 transcription factor-dependent manner. Overall, we find that sex-specific differences in T-reg cells from VAT are determined by the tissue niche in a sex-hormone-dependent manner to limit adipose tissue inflammation.

Visceral adipose tissue contains populations of regulatory T cells that exhibit sexual dimorphism, determined by the surrounding niche, and differ between male and female mice in terms of cell number, phenotype, transcriptional landscape and chromatin accessibility.